Prong and screw plug



Jan. 9, 1951 "H. J. scHooN PRONG AND SCREW PLUG Filed sept. 17, 1947 IN VEN TOR.

Patented Jan. 9, 1951 UNITED STATES 'RTE'NT OFFICE renoue .AND `scmaw PLUG :Harleyl Schoon, Gantcn,-1Ill.

Application September 1'7, 1947, SerialNo.' 774,581

(Cl. .11S-$619 6 Claims. 1 This im/ention` relates to la. prong and .screw plug, and has lfor one of itsobjects'the vproductoncf .a-.simple and eflicient electrical contact plug-wherein the screw plug may be'conveniently moved to :an :extended position and may be freely :rotated `when fin this position .for threading .into

.ascrew socket.

A :further object of this invention zis the Vproduction .of a .simple and eilicient prong .and Ascrew plug, wherein the screw element .may be eicientlylocked in a retracted" position :within the .tion will appear lthroughout the following speci- -cation-andclaims.

in the `drawing:

Figur-e 1 .isa .side :elevational viewof the ip'lug with .the :screw element in an extended position, `the lower threaded cap being shown insection;

Figure l2 is a central `ver-tical sectional view Staken :on `a line .with 'the ring-engaging bayonet slots formed in the skirt casing;

Figure -13 is aside :elevational view of the screw element, certain parts being .shown vin section;

Figure 44 is a perspective view .of the .insulated core element, vone of the contact elements being removed;

Figure 5 isan enlarged top plan view of `the `core element, 'both contact elements being :shown in position;

.Figure 6 is a fragmentary .vertical sectional view 'taken ona line with theslots which receive the anchoring pins, a part of .the core element being shown in section, rand a part of the :screw element being .broken away;

Figur-e `7 is a perspective view of the screw element-actuating .ring which carries the screw element;

Figure 8 isa fragmentary perspective view of theirng shown in Figure 7;

Figure 9 isa perspective viewoi theskirtshell, illustrating the relative locations of the bayonet :slots 'and the slots which receive the anchoring pins.

.By referring 'to the drawing, .it will 'be -seen that |0 designatesr the .skirt casing which is provided with a depending externally threaded portion `for vdetachabl-y receiving the internally threaded cap I2. vThe qdepending threaded portion constitutes a base .to 'which the inner ends |.3 and 14 of the `prongs '1'5 .and t6 are secured iin the manner sho-wn in Figure 2. These prongs vextend through suitable apertures `formed the vportion itl", the apertures being slightly larger than the prongsto facilitate :placing of the prongs in position and also to permit .the prongs Vto slightly flex when'necessary. The lead wires |:1 and .|'8 areeecnnected to the prongs :15 and` lby .means of suitable screws 4I9 andx2it The skirt `casing :t0 vis provided withlongitudk nal diametrically opposite -bayonet slots-2| Atvlzlich extend through the. upper or outer .end A23..of the casing It, as shown indetafil in Figurer). "The respective slots 2| are provided withl opposite'ly extending 'lateral portionsguzat their inner ends for the purpose .described in thezfollowing. A pair-.of anchoring pin-receiving ifslots extend longitudinally -of the .casing IB intermediatezthe bayonet slots 2| .and :the slots 25 .are preferably `arranged in diametrically .opposite relationto .each other. 'The slots25 terminate short .of the outer end 23 of rthe :casing |.0 vandv are .closedat theirzouter ends, as shown.

A :screw element-actuating ring 2B .is slida'bly mounted upon the icasing -Ii'l. This .ring 26 comprises van Aouter band 21 and :an .inner .band 28. These bands 21 .and 253 :are held :in relativelspaced `relation by means of a 4pair of .diametrically opposite integral lugs `129. The hand Zis :adapted 'to' fitv snugly against the inner face of the casing lil., and the band 21 :isadaptedzto tsnugly around lthe outer face of the casing y1|). r4The integral lugs :2B pass throughthe :slots 1:21 and Ypermit the. ring r26 to .slide longitudinally-of .the casing Ml.

Thering 2zcarries aprotruding threaded .meta1 shell 30 'which is provided With .a .depending :inset rim .or skirt 3| :defining a .shoulder 32. "Ille `rim orgskirtl is fixed to. the inner face of the band 28 and the shoulder '.32 is xed to and `.over- .hangs Vthe .outer face` of .the band 28. The shell 30 andthe ring v2.6 therefore constitute .one unitary element, the shell 3|) being formed .of conducting .metal, and `the ring 25` being formed of insulating material.

A core` element `33 formed -of insulating material is carried within the shell 36 and is 'iixed against .rotary .movement within the Vshell 36 by means of anchoring pins 34 which `pass through the slots 25 of the casing ID and are threaded vor otherwise secured in the lower end of the core element 33, as shown .in Figure 6. One or more of these pins 34 may be used without .departing from the spirit of the invention. The pins 34 extend transversely through the slots 2| and into the core element 33 and rabut the outer closed ends oi the slots 25 to limit the outward movemen-t of rthecore element 33 relative to the vouter `end 23 iof "the vcasing it. "The cere element 343 carries a conducting band of metal 35 which overhangs the shoulder 32 ofthe shell 30. The band 35 is xed to the insulating core element 33 and the band 35 holds the core element 33 against independentI longitudinal movement in one direction, while the pin or pins 34 which abut the under face of the ring 26 hold this core element against independent longitudinal movement in the opposite direction relative to the ring 26. The ring 26 which therefore carries the shell 30 and core member 33 may be moved longitudinally of the casing I as one element, from a retracted to an extended position to a point where the lugs 29 of the ring 26 overlie the outer ends of the slots 2I. The ring 26 to which the threaded shell 30 is xed may be freely rotated, the lugs 29 moving circumferentially of the outer end 23 of the casing I0, and the bands 27 and 28 rotating freely around the casing I0. In this manner, the shell 30 may be easily threaded into a threaded or screw socket without rotating the casing I0.

When the ring 26 is moved inwardly of the outer end 23 of the casing I5, the lugs 29 will slide longitudinally of the .slots 2 I, and by slightly turning the ring 26 the lugs 29 may be fastened within the lateral portions 24 of the bayonet slots 2| and thereby removably secure the screw element, comprising the ring 26, the shell 30, and core member 33 in a shielded and retracted position within the casing I0, as shown in Figure 2.

The core member 33 is provided with a longitudinal aperture 36 through which the prong I5 extends, and a longitudinal aperture 37 through which the prong I6 extends. The band 35 is provided with a contact strip 38. This strip 38 is provided with an inturned contact finger 33 which extends downwardly through the outer end of the aperture 36 of the core member 33, to provide a slidable spring contact with the prong I5, which extends through the aperture 36.

A central contact plate 40 is countersunk in the socket 4I formed in the outer end of the core member 33, and is anchored in position by means of the central contact pin or screw 42 of the conventional type, which screw 42 also retains the covering insulating disc 43 of the conventional type in place. l The disc 43 is suitably apertured to permit the prongs I and I6 to extend therethrough. The plate 40 is out out, as at 44, and a spring-bowed Contact finger is bent downwardly therefrom to extend down into the upper or outer end of the aperture 31 of the core element 33 for Contact with the prong I6 when the screw element comprising the ring 26 and shell 33, is extended to the position shown in Figure l. The prong I6 is provided with an offset portion 46 and the outer end of the slot 3T is restricted, as at 41, just beyond the bowed portion of the finger 45 to cause the bowed portion of the finger 45 to break contact with the offset portion 46 when the screw element is in a retracted position. This will break the circuit through the shell 30. As the screw element is moved outwardly of the casing I3 the nger 45 will close the circuit through the prong I6.

As shown in Figure 2, the outer ends of the prongs I5 and I6 preferably are apertured, as at 48. When the screw element is extended to the position shown in Figure l, the outer ends of the prongs I5 and I6 are shielded within the apertures 36 and 3l of the core element 33. The ring 26 and the shell 33, however, may be freely rotated for threading the'shell 30 into a screw socket. l'lhecurrent will then pass through the 4 pin 42 from the receptacle or socket to the plate 40, the linger 45, the prong I6, to the outlet wires I'I and I8, and back through the prong I5, the nger 39, the strip 38, the band 35, and the shell 30 to the receptacle or socket in which the plug issecured.

When the screw element is retracted to the position shown in Figure 2, the prongs I5 and I6 will protrude beyond the screw element and may flt into a prong-receiving receptacle. The current will then pass through prong I6, and back through prong I5, the shell 30 being dead.

From the foregoing description, it will be seen that a very simple and eflicient plug has been produced which may be adjusted for use either as a screw plug or a prong plug.

Having described the invention, what is claimed 1s:

1. A plug of the class described comprising a hollow casing, current-conducting prongs carried by and extending longitudinally of the casing, a screw element movable to a retracted and to an extended position relative to said casing and comprising an actuating ring, a threaded shell fixed to said ring, an insulated core member carried by the ring and fixed against longitudinal movement relative to the ring, the ring and shell being rotatable relative to the core member, means for locking the ring against rotation relative to the casing when the screw element is retracted and releasing the ring for rotation when the screw element is extended to facilitate the threading of the shell into a threaded socket, said scr-ew element being movable to a position beyond the prongs when the screw element is in an extended position, the prongs extending beyond the screw element when the screw element is in a retracted position, a contact terminal carried by the core member, means carried by the core member for electrically connecting one of the prongs to the shell, and means for connecting the other prong to the contact terminal of the core member.

2. A plug of the class described comprising a hollow casing, current-conducting prongs carried by and extendng longitudinally of the casing, a. screw element movable to a retracted and to an extended position relative to said casing and comprising an actuating ring, a threaded shell xed to said ring, an insulated core member carried by the ring and iixed against longitudinal movement relative to the ring, the ring and shell being rotatable relative to the core member, means for locking the ring against rotation relative to the casing when the screw element is retracted and releasing the ring for rotation when the screw element is extended to facilitate the threading of the shell into a threaded socket, said screw element being movable to a position beyond the prongs when the screw element is in an extended position, the prongs extending beyond the screw element when the screw element is in a retracted position, a contact terminal carried by the core member, means carried by the core member for electrically connecting one of the prongs to the shell, means for connecting the other prong to the contact terminal of the core member, and means for breaking the circuit between the last-mentioned prong and said contact terminal when the screw element is retracted.

3. A plug of the class described comprising a hollow casing, current-conducting prongs carried by and extending longitudinally of the casing, a screw element movable to a retractedI and to an extended position relative to said casing and comprising an actuating ring, a threaded shell xed to said ring, an insulated core member carried by the ring and fixed against longitudinal movement relative to the ring, the ring and shell `being rotatable relative to the core member, means for locking the ring against rotation relative to the casing when the screw element is retracted and releasing the ring for rotation when the screw element is extended to fac litate the threading of the shell into a threaded socket, said screw element being movable to a position beyond the prongs when the screw element is in an extended position, the prongs extending beyond the screw element when the screw 4. A plug of the class described comprising a casing, current-conducting prongs carried by and having protruding ends extending beyond said casing, a screw element movable to a retracted and to an extended position relative to said casing and comprising an insulated actuat- :v

ing ring, a conducting threaded shell xed to said ring and constituting one contact terminal, an insulated core member carried by said ring and xed against longitudinal movement relative to said ring; the ring and shell being rotatable relai tive to the core member, said screw element being movable to a position beyond the prongs when the screw element is in an extended position, the prongs extending beyond the screw element when the screw element is in a retracted position, a secondcontact terminal carried by the core member, means electrically connecting one of the prongs to the shell, means electrically connecting the other prong to said second contact terminal, said casing having a longitudinally extending guiding slot, said ring comprising a pair or" spaced insulated bands, one band fitting within said casing, the other band tting around the exterior of said casing, band connecting means normally extending through said guiding slot and connecting said bands to hold the ring against rotation relative to said casing, and the slot being open at the outer end of the casing to facilitate the moving of the band connecting means beyond said casing and to facilitate the rotation of the ring relative to the casing to thread the shell into a screw socket.

5. A plug of the class described comprising a casing, current-conducting prongs carried by and having protruding ends extending beyond said casing, a screw element movable to a retracted and to an extended position relative to said casing rand comprising an insulated actuating ring, a conducting threaded shell fixed to said ring and constituting one contact terminal, an insulated core member carried by said ring and xed against longitudinal movement relative to said ring; the ring and shell being rotatable relative to the core member, said screw element being movable to a position beyond the prongs when the screw element is in an extended position, the prongs extending beyond the screw element when the screw element is in a retracted position, a

second contact terminal carried by the core member, means electrically connecting one of the prongs to the shell, means electrically connecting the other prong to said second contact terminal, said casing having a longitudinally extending guiding slot, said ring comprising a pair of spaced insulated bands, one band tting within said casing, the other band fitting around the exterior of said casing, a lug normally extending through said guiding slot and connecting said bands to hold the ring against rotation relative to said casing, the slot being open at the outer end of the casing to facilitate the moving of the lug beyond said casing and to facilitate the rotation of the ring relative to the casing to thread the shell into a screw socket, and said slot having a lateral socket at its inner end for receiving said lug when the screw element is retracted into said casing to hold the screw element in a retracted position.

6. A plug of the class described comprising a casing, current-conducting prongs carried by and having protruding ends extending beyond said casing, a screw element movable to a retracted and to an extended position relative to said casing and comprising an insulated actuating ring, a conducting threaded shell xed to said ring and constituting one contact terminal, an insulated core member carried by said ring and fixed against longitudinal movement relative to said ring; the ring and shell being rotatable relative to the core member, said screw element being movable to a position beyond the prongs when the screw element is in an extended position, the prongs extending beyond the screw element when the screw element is in a retracted position, a second contact terminal carried by the core member, means electrically connecting one of the prongs to the shell, means electrically connecting the other prong to said second conta-ct terminal, said casing having a longitudinally extending guiding slot, said ring comprising a pair of spaced insulated bands, one band tting within said casing, the other band fitting around the exterior of said casing, band connecting means normally extending through said guiding slot and connecting said bands to hold the ring against rotation relative to said casing, the slot being open 'at the outer end of the casing to facilitate the moving `of the band connecting means beyond said casing and to facilitate the rotation of the ring relative to the casing to thread the shell into a screw socket, and means slid-ably connecting the core and casing and limiting the sliding movement of the core relative to the casing to prevent accidental displacement of the core relative to the casing when the screw element is moved to an extended position.

HARLEY J. SCHOON.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 747,553 Kelsey Dec. 22, 1903 1,897,323 Moorhouse Feb. 14, 1933 2,006,794 Davidson July 2, 1935 2,229,150 Wadsworth Jan. 21, 1941 2,229,151 Wadsworth Jan. 21, 1941 

